This section provides background information related to the present disclosure which is not necessarily prior art.
Due to a demand for clean waste gas and in view of concern about the oil supply and oil costs in recent years, diesel fuels and gasoline-alcohol mixed fuels are becoming more popular. Ethanol (ethyl alcohol) fuel mixtures have “E” numbers which describe the percentage of ethanol in the mixture by volume. For example, E85 is 85% anhydrous ethanol and 15% gasoline. Fuel mixtures having less than 10% ethanol (E0-E10) typically do not require any modifications to modern day vehicles. Fuel mixtures of E10 to E25 may require modifications to the fuel system, but not the basic engine. Fuel mixtures of E25 to E85 may require modification to the fuel system and to the basic engine. Fuel mixtures of E85 to E100 (100% ethanol) may require modifications to the fuel system, modifications to the basic engine and may require some type of cold starting system.
The high alcohol containing fuel, such as E100 which is used in Brazil, has inherent problems such as the low theoretical air-fuel cost as compared with gasoline because the combustion of alcohol is a chemical equivalent combustion and an increase in the latent heat of evaporation of alcohol. Due to an increase in the amount of fuel injected and an increase in heat necessary for evaporation, failure of engine start at low ambient temperature becomes a problem.
One solution to this engine start problem at low ambient temperatures is to equip the vehicle with a second fuel tank typically located next to the engine. The fuel tank is filled with gasoline, not ethanol and the fuel in this tank is used to help start the vehicle under extreme conditions such as cold weather. Should a person forget to fill this second tank, the vehicle may not start. Eliminating this second tank improves safety, provides packaging space under the hood for additional components and potentially reduces overall vehicle costs.
Another solution to this engine start problem at low ambient temperatures is to equip the vehicle with an electric heater that heats up the fuel in a heated fuel injection rail. This system is high cost and it uses a significant amount of electrical power which then requires a larger, heavier and more costly battery.